The success of high performance portable electronics and hybrid (or electric) vehicles strongly depends on further technological progress of commercially available rechargeable batteries. Lithium-ion batteries (LIBs) are considered the most likely energy storage configuration to satisfy these demands. However, this requires significant advances in terms of power density, energy density, cycle life and safety, as well as lower production costs. Current LIBs utilize graphite anodes where energy is stored by intercalating lithium into the graphite layers. This arrangement while commercially successful can only deliver a maximum theoretical capacity of 370 mAhg-1, (Shang W. J.; A review of the electrochemical performance of alloy anodes for lithium ion batteries, J. Power Sources 196, 13-24 (2011)). Incorporating additional components offers the potential to dramatically improve this capacity. For example silicon can provide up to 4200 mAhg-1, in theory, corresponding to the following alloying reaction:4.4 Li+Si→Li4.4Si  (1)While Si-based composites offer immense promise as new generation anode materials, extreme changes in volume during lithiation and delithiation lead to structural degradation and loss of performance over time that impedes their practical application.
Several journal articles as well as patents are concerned with the improving performance and cycle stability of silicon. Magasinski et al. (Nature Material, 9 (2010) 353-358) prepared silicon nanoparticles by silane decomposition onto annealed carbon-black dendritic particles and followed by coating with carbon in a chemical vapour deposition (CVD) process. This paper describes reversible capacities over five times higher than that of the state-of-the-art anodes (1950 mA h g−1) and stable performance. Cui et al. (Nature Nanotechnology, 3 (2008) 31-35) prepared high performance anodes based on silicon nanowires. They prepared the silicon nanowires in a CVD process using the vapour-liquid-solid (VLS) method with gold as a catalyst. The paper describes achieving the theoretical capacity of the silicon anodes and maintained a discharge capacity close to 75% of the maximum. However, this process employs costs catalyst material. Kim et al. (Nano letters, 8, (2008) 3688-3691) prepared a Si core and carbon shell structure by using SBA-15 mesoporous silica material as a template. They reached a first charge capacity of 3163 mA h/g with a coulombic efficiency of 86% at a rate of 600 mA/g, and they retained 87% of their capacity after 80 cycles. However, when they increased the rate capability to 6 A/g the capacity decreased to 78%. In US 2005/0031957 A1, silicon microparticles were mixed with an electrochemically inactive phase that includes an intermetallic compound that is formed of at least two metals and a solid solution yielding a composition of Si55Al30Fe15 (for example). Even though, these electrodes showed improved cycle stability, they had a great loss in specific capacity due to the inclusion of inactive components in the electrode. US 2009/0130562, describes coated silicon nanoparticles with carbon and their use as anode material. The composite material comprising silicon, carbon and graphite showed a capacity of around 900 mAh/g for almost 5 cycles. US 2010/0062338 A1, describes the use of silicon nanoparticles as an active material and an elastomeric binder to bind the silicon nanoparticles as well as the addition of conductive material such as super P or graphite. In this patent the author claims that these electrode additives improved cycle stability of the battery; however, they did not disclose specific performance results. In US 2012/0121977 A1, the inventors describe an interfacial layer around the silicon nanoparticle. The layer has good electron conductivity, elasticity and adhesion. This layer is formed of a monomer and a polymer with several functional groups. The capacity is about 400 mAh/g and increasing with the cycle number up to a maximum at about 1000 mAh/g at about 100 cycles then decay back during the next 100 cycles reaching 700 mAh/g at the 200th cycle. In US 2012/0129054, the inventors used silicon nanowires with or without carbon coating and also they claim the addition of diallyl pyrocarbonate to the electrolyte during the battery fabrication.
US2014/0186701 to Zhang et al. describes a composite anode prepared by electrophoretic deposition (EDP) of a suspension comprising one or more of silicon, carbon and a current collector onto a copper current collector and allowing the deposited material to dry on the carbon substrate.
Despite the various approaches proposed in the literature, there is no approach to directly use commercially available silica nanoparticles with affordable, economic and environmentally safe treatment methods for fabrication of lithium ion batteries. There remains a need for a solution to prevent the loss in specific capacity due to addition of inactive materials needed to enhance stability. There further remains a need for a method to prepare anode that are stable and provide sufficiently high performance at an acceptable cost.